In various communication systems, a subcarrier may be modulated to communicate information. For example and without limitation, in a video communication system, video information may be communicated by phase-modulating a subcarrier. For example, the NTSC and PAL video standards include communicating color (or chroma) information by phase-modulating a subcarrier. In such systems, determining phase of the subcarrier (e.g., the reference subcarrier and/or modulated subcarrier) is generally part of the process of demodulating the subcarrier to obtain the communicated information.
During communication, subcarrier phase may be adversely affected by any of a number of factors (e.g., resulting in subcarrier jitter). For example and without limitation, interference by other communication signals (e.g., wired or wireless signals) may alter the subcarrier phase. Also for example, natural or manmade physical obstacles and/or non-communication signals emanating from natural or manmade systems may alter the subcarrier phase.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with the present invention as set forth in the remainder of the present application with reference to the drawings.